MasterCraft transmission ratios

[GMC]

Recently a couple friends have purchased used MC Tournament Team boats - one with the 6.0l and one with the MCX.  Apart from expected differences in propellers (the 6.0 had a jump prop on it), we've also noticed the slight difference in transmission ratio:  the 6.0l apparently has a 1.22:1 and the MCX has a 1.26:1.  Looking at the two MC's posted recently in the classifieds here, it's exactly the opposite:  The 6.0l has the 1.26:1 and the MCX has the 1.22:1.  If the analogy fits, axle ratios on cars are much more coarse: 2.73, 3.08, 3.42, etc.  In both cases, tire radius and propeller specs can be used for fine tuning.  A 0.04 difference in ratio seems very, very small (almost insignificant?) to me.

I'm also assuming both ratios are USAWS approved; I know they went from 1.5:1 to 1.26:1 in 2005 but when did the 1.22:1 appear and why? 

BTW I love that 190.  If I was in the market for a boat, that would be very high on my list - if it didn't have that 6.0l.  Then again, if that was your practice boat, everything would probably feel soft...

[east tx skier]

I saw your post a while ago and just didn't know the answer.  I read it again and got curious.

 

For starters, I have never heard of the 1.22:1 gearing on a MC.  It used to be that you had 1:1 or the 1.52:1 Powerslot.  Then, as you mention, roughly around 2005, they went 1.26:1 on nearly everything (as far as tournament specific boats), but kept the 1.52:1 for the big block and/or jump.  I was under the impression that the 1.52:1 had been completely phased out on the direct drives.  But ...

 

I just looked at the AWSA approved towboat list for 2009.  The 190 is only listed as approved with the 1.22:1 gearing coupled with the LY6 6.0L engine.  The 197 is listed as approved with both the 1.26:1 paired with the MCX 5.7L or the LQ9 6.0L with the 1.56:1 (what?) ratios.  The 214 is approved with the 1:1 paired with the MCX (first time they've tested and approved a 1:1 since 2005).  

 

Looks to me like they're pairing transmissions with engines, at least in the tournament team boats.  The gear reduced transmissions were always explained to me as simply a means of turning a bigger wheel under the water.  In this instance, the 1.22:1 turns a 14.25x14; 1.26:1 turns a 13.7x15; 1.56:1 turns a 14.25. 

So here's my uneducated guess.  The 197 got two test boats because they're selling more of them to their tournament guys.  One of these boats is a straight up slalom tug with the popular MCX and the standard gear reduction of 1.26.  This seems like the more universal slalom friendly configuration.  The other 197 is a jump boat.  Big engine, transmission for pulling tractors out of the mud, and a huge wheel.  The 190 gets one test boat for the purists that live for the closed bow (I recall they only produced around 6--8 190's in 2006 for example).  Big engine and wheel for the jumpers, but the transmission is scaled down for a softer pull in the course leaving the torque to the engine.

Jump is obviously a big part of their motivation these days.  What do the ads say, "Freddie Broke Another Record!"  They are making sure that all of the tournament boats are jump capable.

P.S.  I've got your question in to a friend of mine close to the source.  I'll let you know how wrong my guess was.

[Bill Gladding]

I am guessing the reduction is engine specific most likely to achieve a specific speed, keep the propeller size within a certain range and the engine turning on the sweet spot.

 

[east tx skier]

Bill, per my source, you are correct.  Prop and engine combos listed are for the purpose of getting the boat at or near 1:1 in the course, which apparently is not so great if for the jumpers.

[GMC]

Interesting, thanks for the responses.  I'm kinda surprised (and kinda glad) that level of effort goes into powertrain matching.